Jahvid Best return: Is it 'when' or 'if?'

In a matter of hours, we've gone from good news to bad news in the Detroit Lions' backfield. Mikel Leshoure returned to practice Wednesday, but ESPN's Adam Schefter has reported that Jahvid Best is likely to be sidelined for at least the first six weeks of the regular season.

Best has yet to be cleared for contact nearly 10 months after suffering a season-ending concussion on Oct. 16, 2011. The Lions thought he would be ready for the start of training camp, and general manager Martin Mayhew said last month that he was "very comfortable" in predicting that Best would eventually be cleared. Now, it seems fair to question whether he will be cleared in time to play this season.

There is obviously much more going on behind the scenes than we know, and concussion recovery doesn't follow the same trajectory as, say, knee injuries or broken arms. But common sense, at least, leads us to wonder about the wisdom of returning from an injury that -- if he remains on the PUP -- will sideline Best from football activities for at least a full calendar year.

The way NFL rules work, the Lions could extend Best's recovery time through Week 12 of the season without having him count against their roster. To do that, however, he would have to begin practicing by Week 9. (He wouldn't be eligible to practice before Week 7.)

There is no way of knowing from our vantage point whether the extra time on the PUP will work to Best's advantage or merely delay the inevitable. But concern should grow every time it appears that his projected return has been pushed back. At this point, anything the Lions get from Best this season should be considered a bonus.